What medium first delivered C.S. Lewis’s Mere Christianity to a broad public?

C.S. Lewis’s Mere Christianity first reached a broad public through BBC radio broadcasts.

During the Second World War, Lewis gave a series of radio talks for the BBC. The broadcasts began in 1941 and continued in later series, presenting basic Christian ideas in accessible language for a general audience. Their success made Lewis widely known beyond academic and literary circles.

The talks were later revised and gathered into books. The material eventually became Mere Christianity, first published in book form in 1952. The title refers to the shared core of Christian belief rather than to one specific denomination.

A common mistake is to describe Mere Christianity as a book written before the broadcasts. Its published form grew out of the radio talks, though Lewis edited and reorganized the material for print. The wartime setting also shaped the work’s direct, conversational tone, which was designed for listeners rather than specialist readers.